. >> with the first of our year-enders, here's abc's karen travers. >> reporter: to win a second term, president obama had to overcome a well funded opponent, a struggling economy, and voters' doubts that he had the right agenda to turn the nation around. [ chanting ] >> all: four more years! >> reporter: and after a roller coaster season, he got them. mitt romney may have started off at the frontrunner, but to win the republican nomination, he had to fend off some feisty challengers. >> he's the worst republican in the country to put up against barack obama. >> the odds are very high i'm going to be the nominee. >> reporter: and overcome some self-inflicted wounds. >> i like being able to fire people who provide services to me. >> reporter: after nearly 50 primary contests, romney finally clenched the nomination and it was on to the general election. >> it will be a choice between -- >> two very different paths. >> reporter: their battle focused on the economy. the overwhelming top issue to voters. >> we can't afford another four years like the last four years. >> we need more tax cu